Digestive Diseases and Sciences, Vol. 50, No. 5 (May 2005), pp. 885–892 ( C  2005) DOI: 10.1007/s10620-005-2660-3 Analysis of Canine Model of Gastric Electrical Uncoupling Using Recurrence Quantification Analysis C. NEWTON PRICE,* D. T. WESTWICK,* and M. P. MINTCHEV, P.Eng*† This study reports the results of recurrence quantification analysis (RQA) applied to internal gastric electrical activity (GEA) and cutaneous electrogastrographic (EGG) digital recordings obtained from acute canine models. The purpose of this chaos analysis is to differentiate three states— normal, mild, and severe induced electrical uncoupling—utilizing five quantities associated with RQA: percent recurrence, percent determinism, maximum deterministic line, entropy, and trend. The results indicate that percent recurrence and trend are the only quantities that relate the three states of gastric electrical uncoupling in any meaningful way. The ability of EGG to detect mild electrical uncoupling in the stomach appears to be limited due to the impact of numerous external factors on the signals, even if multichannel recordings are utilized. KEY WORDS: gastric electrical activity; electrogastrography; recurrence quantification analysis. The stomach is responsible for grinding, mixing, and transporting food from the esophagus to the small intestines. These responsibilities are of considerable im- portance for the overall functioning of the entire gastroin- testinal system. Therefore, being able to determine any change in the normal motility of the stomach is of sig- nificant value. Since the control of gastric motor function is electrical in nature, measurement of cutaneous and in- ternal gastric electrical activity (GEA) has been consid- ered an avenue to assess gastric function dynamics (1). Internally, gastric electrical signals are usually obtained by placing electrodes subserosally, a very invasive mea- surement generally referred to as GEA (2). Cutaneous ob- servation of GEA is obtained by placing bipolar electrodes on the abdominal wall of the subject and recording from single or multiple channels, a non-invasive method known Manuscript received April 21, 2003; accepted June 14, 2003. From the *Department of Electrical and Computer Engineering, Uni- versity of Calgary, Calgary, Alberta, Canada T2N 1N4, and †Department of Surgery, University of Alberta, Edmonton, Alberta, Canada T6G 2B7. Address for reprint requests: Dr. Martin P. Mintchev, Room A121A, Engineering Complex, University of Calgary, 2500 University Drive, NW, Calgary, Alberta, Canada T2N 1N4; mintchev@enel.ucalgary.ca. as electrogastrography (EGG) (2). The processing of the EGG signals currently follows traditional methods such as Fourier analysis, in which the frequency spectra of the signals are obtained to identify irregularities in EGG based on frequency dynamics (1, 3). This traditional approach brings about two problems. The first is related to the anal- ysis of EGG recordings from individuals with gastric elec- trical uncoupling (3, 4). Gastric electrical uncoupling is the loss of synchronization in the sequential peristaltic con- tractions of the stomach, causing the inability of the organ to propel content distally in a synchronized fashion. Early detection of electrical uncoupling could be important in assessing gastric motility abnormalities, compared to the so-called “gastric dysrhythmias,” which might not signif- icantly affect gastric motor function if they are synchro- nized throughout the distal corpus and in the antrim (4). Detection of electrical uncoupling by statistically exam- ining the EGG frequency spectra failed to recognize mild uncoupling (3), suggesting that Fourier analysis is proba- bly not sufficient to identify the onset of this condition. The second problem is related to a recent finding that EGG sig- nals may in fact be chaotic (4). The implication of this find- ing downgrades the usability of traditional methods, such Digestive Diseases and Sciences, Vol. 50, No. 5 (May 2005) 885 0163-2116/05/0500-0885/0 C  2005 Springer Science+Business Media, Inc.